Pharmaceutical composition for relieving pain

ABSTRACT

The present invention relates to a pharmaceutical composition for relieving pain in a joint disease, including a hyaluronic acid and a pharmaceutically acceptable carrier, in which the hyaluronic acid is cross-linked by cyclizing a double bond in the moiety of a cinnamic acid in a partially amidated hyaluronic acid represented by Formula (1):
 
[Ar—CH═CH—COO—(CH 2 ) n —NH-] m -HA,
 
to form a cycloubutane ring, in which Ar represents an optionally substituted phenyl group, n represents an integer of 2 or 3, HA represents a carboxy residue of the hyaluronic acid, and m represents an amidation ratio of the hyaluronic acid to the total carboxyl group and is in the range of 3 to 50% relative to the total carboxyl group.
 
     The pharmaceutical composition of the present invention is an intra-articular formulation that exerts rapid analgesic effects after administration, and shows extremely long durable effects for a human joint disease with only a single administration rather than multiple administrations of a conventional way.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a 35 U.S.C. §371 U.S. national entry ofInternational Application PCT/JP2010/005060 (WO 2011/018902) having anInternational filing date of Aug. 13, 2010, which claims under 35 U.S.C.§119(a) the benefit of Japanese Application No. 2009-187899, filed Aug.13, 2009, the entire contents of which are incorporated herein byreference.

TECHNICAL FIELD

The invention relates to a pharmaceutical composition for relieving painin joint disease including a cross-linked hyaluronic acid and apharmaceutically acceptable carrier.

BACKGROUND ART

In the aging modern society, osteoarthritis (hereinafter, referred to asOA), which is joint pain and functional disorder attributable to jointdegeneration, is the most common joint disease throughout the world, andis one of the leading causes of disability in daily life of the elderly.

Currently, OA treatments include, for example, a treatment by oraladministration of analgesic drug such as non-steroidal anti-inflammatorydrug, which is broadly used for various pains, and a treatment byintra-articular administration of hyaluronic acid solution.

The former treatment is a symptomatic therapy for relieving joint painwith use of a synthetic medicine having sharp analgesic effects.

On the other hand, the latter treatment is a therapy for treating jointdisease, which is impaired joint function attributable to reduction ofthe joint fluid and degeneration of joint cartilage, by lubricantaction, shock absorber action, cartilage metabolism improvement actionand joint pain relieving action, which are possessed by the hyaluronicacid.

Hereinafter, hyaluronic acid or a derivative group therefrom may bereferred to as HA.

Currently, intra-articular formulations using hyaluronic acid andderivative thereof (hereinafter, referred to as the IA-HA product.) arecommercially available as products formed from solution of sodiumhyaluronate, and products formed from solution of a cross-linkedhyaluronic acid derivative. Examples of the IA-HA products formed fromsolution of sodium hyaluronate include ARTZ (registered trademark),SYNVISC (registered trademark), HYALGAN (registered trademark), andORTHOVISC (registered trademark). Examples of the IA-HA product formedfrom solution of a cross-linked hyaluronic acid derivative includeSYNVISC (registered trademark) and DUROLANE (registered trademark).SYNVISC (registered trademark) is composed of a hyaluronic acidderivative cross-linked with a covalent bond by a small amount ofaldehyde, and a hyaluronic acid derivative made by further cross-linkingthe derivative by divinyl sulfone. DUROLANE (registered trademark) is anepoxy cross-linked joint protective agent (see U.S. Patent ApplicationPublication No. 2006/0148755).

These IA-HA products are administered basically every 1 to 2 weeks toobtain desired therapeutic effects (see “The Journal of Rheumatology”2004, 31: 4, pp. 775-782; and “Current Medical Research and Opinion” 11:205-213, 1988). Since hyaluronic acid has viscoelasticity,intra-articular administration of these IA-HA products is performed withuse of a thicker injection needle than that for usual injections.Therefore, the intra-articular administration of these IA-HA productsgives the feels of more invasion and boring pain than administration ofusual injections, and the administration of these IA-HA products in thesingle treatment period is limited to 5 times in principle in Japan.However, conventional products require continuous administrations everyweek, which may become a great burden to patients who reside at adistant place from the hospital or who have difficulty in visitingweekly owing to the job of the patients. Accordingly, products requiringadministrations at fewer frequencies and showing equivalent or bettertherapeutic effects to or than those of the conventional IA-HA productsare sought.

Recently, there has been reported a product (SYNVISC-ONE (trademark))that is a new regimen using SYNVISC (registered trademark) and allows asingle injection with increased dosage up to three times a usual dosage(2 mL) of conventional products. According to the report, it is believedsuch that the therapeutic effects last for 26 weeks after a singleadministration (see “ARD Online First,” published on Mar. 19, 2009 as10. 1136/ard. 2008. 094623). However, such therapeutic effects are onlyresults from the single administration with three-time dose (6 mL) ofthe conventional product. Further, there is also a demerit that a burdento patients is increased by triple dose intra-articular injection at oneshot compared to the conventional product.

In addition, International Publication Pamphlet No. WO 2008/069348reports a therapeutic agent for a joint disease for intra-articularadministration by a photo cross-linked hyaluronic acid derivative, whichis a different cross-linked form from that of the commercially availablecross-linked hyaluronic acids, and has durable effects with a singleadministration. However, there is no specific disclosure or suggestionregarding the ultralong-term durability inhuman OA treatment.

In addition, IA-HA products are focused on long term enhancement ofpatient's QOL by improving comprehensive joint functions, and hardlyexpected to have rapid-acting analgesic effects as expected in, forexample, non-steroidal anti-inflammatory analgesic drugs (see “TheJournal of Rheumatology” 2004, 31: 4, pp. 775-782; “OsteoArthritis andCartilage” (2004) 12, 642-649; “ARD Online First,” published on Mar. 19,2009 as 10. 1136/ard. 2008. 094623; “Arthritis & Rheumatism,” Vol. 43,No. 9, pp. 1905-1915 (2000)).

As described above, a number of IA-HA products exist, but there has beenno report of an intra-articular formulation that shows equivalent orbetter effects with a single administration to or than the effects shownwith multiple administrations of any of conventional IA-HA products,without an increase of the single dosage, and for a long period,particularly more than a half year from the viewpoint of invasion.

Consequently, desired are products that can have early onset ofprominent analgesic effects, with a lower frequency of administrationand a smaller dosage of a single administration as possible, and showequivalent or better therapeutic effects to or than conventional IA-HAproducts.

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

An object of the present invention is to provide an intra-articularformulation that exerts rapid analgesic effects after administration,and shows extremely long durable effects for human joint disease withonly a single administration rather than multiple administrations, inwhich a dosage of the single administration is substantially no changefrom the dosage of the single administration of the conventional IA-HAproducts which are served with multiple administrations, and the like.

Means for Solving the Problems

The inventors of the present invention have studied earnestly to solvethe above problems, and as results, found that when a cross-linkedhyaluronic acid having short-chain amino alcohol as a spacer is used, itshows early pain alleviation effects whereas conventional IA-HA productsshow no such early pain alleviation effects. In addition, the inventorshave found that such product shows extremely long durable effects, forexample, over a half year for a human joint disease with only a singleadministration of a dosage that is nearly no change from the singledosage of the conventional IA-HA products that are served with multipleadministrations, whereby to complete the invention.

According to one aspect of the present invention, there is provided apharmaceutical composition for relieving pain in a joint disease,including a hyaluronic acid and a pharmaceutically acceptable carrier,in which the hyaluronic acid is cross-lined by cyclizing a double bondin a moiety of a cinnamic acid in a partially amidated hyaluronic acidrepresented by Formula (1):[Ar—CH═CH—COO—(CH₂)n-NH-]m-HA  (1)to form a cyclobutane ring, in which Ar represents an optionallysubstituted phenyl group, n represents an integer of 2 or 3, HArepresents a carboxy residue of a hyaluronic acid, and m represents anamidation ratio of the hyaluronic acid to the total carboxyl group andrepresents 3 to 50% relative to the total carboxyl group.

The content of the cross-linked hyaluronic acid in this pharmaceuticalcomposition is preferably 0.5 to 3.0% by weight per volume relative tothe total product.

In addition, this pharmaceutical composition is desirably in asingle-dose preparation. In this case, this pharmaceutical compositionis preferably administered at an administration interval of 13 weeks ormore.

In addition, this pharmaceutical composition is preferably used fordurable effects up to at least 13 weeks, more preferably for durableeffects up to at least 26 weeks.

The present invention will be more specifically described below.

(1) A pharmaceutical composition for relieving pain in a joint disease,including a hyaluronic acid and a pharmaceutically acceptable carrier,the hyaluronic acid being cross-linked by cyclizing a double bond in amoiety of a cinnamic acid in a partially amidated hyaluronic acidrepresented by Formula (1):[Ar—CH═CH—COO—(CH₂)n-NH-]m-HA  (1)

(in which Ar represents an optionally substituted phenyl group, nrepresents an integer of 2 or 3, HA represents a carboxy residue of ahyaluronic acid, and m represents an amidation ratio of a hyaluronicacid to the total carboxyl group and represents 3 to 50% relative to thetotal carboxyl group), to form a cyclobutane ring.

(2) The pharmaceutical composition as described in the above (1),wherein a ratio (a degree of cross-linking) of the double bond in amoiety of a cinnamic acid which forms a cyclobutane ring by cyclizing is5 to 40%.

(3) The pharmaceutical composition as described in the above (1) or (2),wherein the content of the cross-linked hyaluronic acid is 0.5 to 3.0%by weight per volume of the total product.

(4) The pharmaceutical composition as described in any one of the above(1) to (3), wherein the pharmaceutical composition is an injectionproduct.

(5) The pharmaceutical composition as described in the above (4),wherein a single dosage of the injection product is 2 to 3 mL.

(6) The pharmaceutical composition as described in any one of the above(1) to (5), wherein the pharmaceutical composition is a single-dosepreparation.

(7) The pharmaceutical composition as described in the above (6),wherein the single-dose preparation is administered at an administrationinterval of 13 weeks or more.

(8) The pharmaceutical composition as described in any one of the above(1) to (7), wherein the pharmaceutical composition is used for durableeffects up to at least 13 weeks.

(9) The pharmaceutical composition as described in the above (8),wherein the pharmaceutical composition is used for durable effects up toat least 26 weeks.

(10) A hyaluronic acid cross-linked by cyclizing a double bond in amoiety of a cinnamic acid in a partially amidated hyaluronic acidrepresented by Formula (1):[Ar—CH═CH—COO—(CH₂)n-NH-]m-HA  (1)

(in which Ar represents an optionally substituted phenyl group, nrepresents an integer of 2 or 3, HA represents a carboxy residue of ahyaluronic acid, and m represents an amidation ratio of a hyaluronicacid to the total carboxyl group and represents 3 to 50% relative to thetotal carboxyl group), to form a cyclobutane ring, for use as apharmaceutical composition for relieving pain in a joint disease.

(11) The hyaluronic acid as described in the above (10), wherein a ratio(a degree of cross-linking) of the double bond in a moiety of a cinnamicacid which forms a cyclobutane ring by cyclizing is 5 to 40%.

(12) The hyaluronic acid as described in the above (10) or (11), whereinthe content of the cross-linked hyaluronic acid in the pharmaceuticalcomposition is 0.5 to 3.0% by weight per volume of the totalpharmaceutical composition.

(13) The hyaluronic acid as described in any one of the above (10) to(12), wherein the pharmaceutical composition is used as an injectionproduct.

(14) The hyaluronic acid as described in the above (13), wherein asingle dosage of the injection product is 2 to 3 mL.

(15) The hyaluronic acid as described in any one of the above (10) to(14), wherein the pharmaceutical composition is a single-dosepreparation.

(16) The hyaluronic acid as described in the above (15), wherein thesingle-dose preparation is administered at an administration interval of13 weeks or more.

(17) The hyaluronic acid as described in any one of the above (10) to(16), wherein the pharmaceutical composition is used for durable effectsup to at least 13 weeks.

(18) The hyaluronic acid as described in the above (17), wherein thepharmaceutical composition is used for durable effects up to at least 26weeks.

(19) A method for relieving pain of a patient in need of pain relief ina joint disease, including an administration of an effective dose of ahyaluronic acid and a pharmaceutical composition comprisingpharmaceutically acceptable carrier, the hyaluronic acid beingcross-linked by cyclizing a double bond in a moiety of a cinnamic acidin a partially amidated hyaluronic acid represented by Formula (1):[Ar—CH═CH—COO—(CH₂)n-NH-]m-HA  (1)

(in which Ar represents an optionally substituted phenyl group, nrepresents an integer of 2 or 3, HA represents a carboxy residue of ahyaluronic acid, and m represents an amidation ratio of a hyaluronicacid to the total carboxyl group and represents 3 to 50% relative to thetotal carboxyl group), to form a cyclobutane ring, to a patient in needof pain relief in a joint disease.

(20) The method as described in the above (19), wherein a ratio (adegree of cross-linking) of the double bond in a moiety of a cinnamicacid which forms a cyclobutane ring by cyclizing is 5 to 40%.

(21) The method as described in the above (19), wherein the content ofthe cross-linked hyaluronic acid in the pharmaceutical composition is0.5 to 3.0% by weight per volume of the total pharmaceuticalcomposition.

(22) The method as described in the above (19), wherein thepharmaceutical composition is an injection product.

(23) The method as described in the above (22), wherein a single dosageof the injection product is 2 to 3 mL.

(24) The method as described in the above (19), wherein thepharmaceutical composition is a single-dose preparation.

(25) The method as described in the above (24), wherein the single-dosepreparation is administered at an administration interval of 13 weeks ormore.

(26) The method as described in the above (19), wherein thepharmaceutical composition is used for durable effects up to at least 13weeks.

(27) The method as described in the above (19), wherein thepharmaceutical composition is used for durable effects up to at least 26weeks.

Effects of the Invention

The present invention provides a hyaluronic acid product that has earlyonset of improvement effects for pain in joint disease. In addition, thepresent invention provides a single-dose preparation of which the dosageis substantially the same as that of the conventional one. Thepharmaceutical composition of the invention shows rapid pain improvementeffect after administration. Since this rapid effectiveness is not seenin the conventional IA-HA products, there is a potential that the activeingredient of the invention has different mechanisms from those of theconventional IA-HA products. In other words, it has been found for thefirst time in the invention that the cross-linked hyaluronic acid usedin the invention has such potential.

In addition, the pharmaceutical composition of the invention showsextremely long durable effects for human joint disease simply with onlya single administration of a dose that is nearly no change from thesingle dosage of conventional IA-HA products, which requires multipleadministrations. The treatment is completed with a single administrationwithout an increase of the injection burden to patients, and thus therisk of infections by microorganisms at the time of the injectiondecreases, and patients are also relieved from multiple boring pains. Inaddition, such effects are durable for an extremely long period,resulting in alleviation of burdens of the hospital visits and medicalcost for patients. Furthermore, the administration interval may beextremely extended, so that it allows continuous treatments by the IA-HAproducts.

Furthermore, the pharmaceutical composition of the invention exhibitsless side-effects, and is particularly preferable as a pharmaceuticalcomposition.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating pain-relieving effects from 1 week to13 weeks after the administration for the cross-linked hyaluronic acidderivative group and the PBS group. The horizontal axis represents weeksafter the administration, and the vertical axis represents thedifference (mm) between the pre-administration reference value(Baseline) and the VAS value at each week. The vertical lines on chartthat extend up and down of the plot at 1, 3, 6, 9 and 13 weeks representthe standard deviation. The marks “•” represent the results of thecross-linked hyaluronic acid derivative group, and the marks “▪”represent the results of the PBS group.

MODE FOR CARRYING OUT THE INVENTION

<1> Active ingredient

The active ingredient of the invention is a hyaluronic acid that iscross-linked by cyclizing a double bond in the moiety of a cinnamic acidin a partially amidated hyaluronic acid represented by the followingFormula (1);[Ar—CH═CH—COO—(CH₂)n-NH-]m-HA  (1)

(wherein Ar represents an optionally substituted phenyl group, nrepresents an integer of 2 or 3, HA represents a carboxy residue of thehyaluronic acid, and m represents an amidation ratio of the hyaluronicacid to the total carboxyl group and represents 3 to 50% relative to thetotal carboxyl group), to form a cyclobutane ring. Hereinafter, thiscompound is referred to as the “cross-linked HA derivative.”

The HA that composes this cross-linked HA derivative is not particularlylimited as long as it has a disaccharide unit as a constituent unit, inwhich N-acetyl-D-glucosamine and D-glucuronic acids are bound to eachother with a β1,3 bond, and it is glycosaminoglycan constituted byrepetitive bonds of such disaccharide units by a β1,4 bond. In addition,the HA may be free from formation of a salt, or may form apharmaceutically acceptable salt.

Examples of the pharmaceutically acceptable salts of the HA includealkali metal ion salts such as sodium salts and potassium salts,alkaline-earth metal ion salts such as magnesium salts and calciumsalts, salts with an inorganic base such as ammonium salts, and saltswith an organic base such as diethanolamine, cyclohexylamine, and anamino acid. More preferable example of the salt of the HA is alkalimetal ion salts. Particularly preferable example is sodium ion salt.

The HA may be any of those which are derived from natural productsobtained by extraction of a part of living organisms such as cock'scomb, umbilical cord, cartilage and skin; those which are chemicallysynthesized; or those which are produced by culture or geneticengineering procedures using microorganisms such as yeast. Since thecross-linked HA derivative of the invention is administered to a livingorganism, the cross-linked HA derivative is preferably high-purity HAthat contains nearly no substance, incorporation of which is notpharmaceutically acceptable.

The weight average molecular weight of the HA is not particularlylimited, and is, for example, 10000 to 5000000. The weight averagemolecular weight of the HA is preferably 200000 to 3000000, and morepreferably 500000 to 2500000.

In the cross-linked HA derivative, a substance in which a carboxyl groupin such HA and a cinnamic acid aminoalkyl ester are amide-bounded toeach other (hereinafter, referred to as the “photo-reactive HAderivative.”) exists as a premise. Such substances are cross-linked witheach other intermolecularly and/or intramolecularly by forming acyclobutane ring in the moiety of the double bond of the cinnamic acidaminoalkyl ester residue.

In the Formula (1), the n represents the length of the alkylene moietyin the cinnamic acid aminoalkyl ester, and is preferably 2 or 3. Inother words, the carbon is preferably present in the number of 2 or 3,and particularly has a linear structure. Examples thereof include anethylene group or a trimethylene group. Examples of the cinnamic acidester in the invention include a cinnamic acid 2-aminoethyl ester and acinnamic acid 3-aminopropyl ester. A preferable example of the cinnamicacid ester is cinnamic acid 3-aminopropyl ester. In the descriptionbelow, the cinnamic acid 3-aminopropyl ester is briefly referred to ascinnamic acid aminopropyl ester, and explanation will be given on suchbasis. It will be easily understood that cinnamic acid aminoethyl estermay be used instead of the cinnamic acid aminopropyl ester that will beexplained below.

The photo-reactive HA derivative can be manufactured by allowing theamino group derived from aminopropanol, which composes the cinnamic acidaminopropyl ester, to bind to the carboxyl group of the HA by theamide-bond.

Such cinnamic acid aminopropyl ester is an ester compound in which thecarboxyl group of a cinnamic acid and the hydroxyl group of3-aminopropanol are bound to each other by the ester bond. This cinnamicacid aminopropyl ester may form a cyclobutane ring by allowing thevinylene groups to bind to each other, which are possessed by thecinnamic acid. The vinylene group possessed by the cinnamic acid has aproperty of causing photo dimerization reaction or photo polymerizationreaction by light (ultraviolet) irradiation. Therefore, the cyclobutanering is formed from two vinylene groups by light irradiation. Inaddition, the cinnamic acid that composes the cinnamic acid3-aminopropyl ester may be a substituted cinnamic acid having asubstituent.

Ar in the Formula (1) represents an optionally substituted phenyl. WhenAr in the Formula (1) is a phenyl group having no substituent, thecompound of the Formula (1) is a cinnamic acid ester. Meanwhile, when Aris a phenyl group having a substituent, it is a substituted cinnamicacid ester. Examples of such substituent, which replaces any one or twohydrogens on the benzene ring of cinnamic, include a C₁₋₈ linear orbranched lower alkyl group (for example, methyl, ethyl, propyl,isopropyl, butyl, t-butyl and the like), a C₁₋₈ linear or branched loweralkoxy group (for example, methoxy, ethoxy, propoxy, isopropoxy, butoxyand the like), an amino group optionally substituted with the alkylgroup, a hydroxyl group, a halogen and the like.

All of the carboxyl groups in the HA in the photo-reactive HA derivativeare not necessarily amide-bounded to the cinnamic acid aminopropylester, but only some of the carboxyl groups may be amide-bounded to thecinnamic acid aminopropyl ester.

The m in the Formula (1) represents a ratio (%) of the amide bond to thecinnamic acid aminoalkyl ester, to the total carboxyl group of HA.Hereinafter, the ratio m of the carboxyl group, which forms the amidebond, to the total carboxyl group present in HA is referred to as the“degree of substitution” (DS). The DS is calculated with theintroduction ratio (%) of the cinnamic acid aminopropyl ester residueper disaccharide unit constituting HA. For example, the DS of thephoto-reactive HA derivative to which one cinnamic acid aminopropylester residue is introduced per constituting disaccharide unit, or theDS of the photo-reactive HA derivative to which one cinnamic acidaminopropyl ester residue is introduced per constituting 200 saccharideunits, are 100% and 1%, respectively.

The DS in the photo-reactive HA derivative in the invention, i.e., theratio m is not particularly limited, but preferably 3% to 50%, morepreferably 5% to 30%, and further more preferably 10% to 25%.

The cross-linked HA derivative used in the invention can be manufacturedin accordance with methods described in the publications of JapanesePatent Application Laid-Open (JP-A) No. 2002-249501 and InternationalPublication Pamphlet No. WO 2008/069348.

The manufacturing method is not particularly limited as long as it makesa cinnamic acid aminopropyl ester and HA chemically bind to each otherby the amide bond. Examples of the method include a method of using awater-soluble condensation agent such as water-soluble carbodiimide (forexample, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride(EDCI.HCl) and1-cyclohexyl-3-(2-morpholinoethyl)carbodiimide-metho-p-tolu enesulfonate; a method of using a condensing aid such asN-hydroxysuccinimide (HOSu) and N-hydroxybenzotriazole (HOBt) with theabove condensation agent; a method of using a condensation agent such as4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride(DMT-MM); an active esterification method; and an acid anhydride method.

The photo-reactive HA derivative may be prepared by making cinnamic acidand aminopropanol (for example, 3-aminopropanol, which is the samebelow) react to each other beforehand in order to prepare a cinnamicacid aminopropyl ester (for example, cinnamic acid 3-aminopropyl ester,which is the same below.), and subsequently making the amino group ofthe prepared cinnamic acid aminopropyl ester and the carboxyl group ofthe HA bind to each other by the amide bond. Alternatively, thephoto-reactive HA derivative may be prepared by making the amino groupof aminopropanol and the carboxyl group of HA to bind to each other bythe amino bond in order to prepare aminopropanol-introduced HA, and thenmaking the carboxyl group of cinnamic acid and the aminopropanol-derivedhydroxyl group in the prepared aminopropanol-introduced HA bind to eachother by the ester bond.

The cross-linked HA derivative is a compound in which the photo-reactiveHA derivatives as described above are bound to each other by forming acyclobutane ring in the double bond moiety of the cinnamic acid propylester residue existing in such derivative.

The method of forming a cyclobutane ring in the double bond moiety ofsuch cinnamic acid propyl ester residue is not particularly limited, andis, for example, a method of performing light irradiation to a solutionof the photo-reactive HA derivative under the conditions in which suchcinnamic acid propyl ester residues cause photo-dimerization orphoto-polymerization to each other. Regarding the light irradiation, thekind, the wavelength, and the like of light are not particularly limitedif the light can cause a photo reaction to the cinnamic acid propylester residue without cleavage of the HA glycosidic bond. The light is,for example, the ultraviolet rays having a wavelength of 200 to 400 nm.The intensity of the irradiation light may be suitably selecteddepending on the properties demanded for the cross-linked HA derivative.The light-illuminating device is preferably an ultraviolet lamp, a highpressure mercury lamp or a metal halide lamp or the like. If necessary,unnecessary wavelength of the light is preferably removed with, forexample, a cut filter and the like from the light source.

In regard to the cross-linked HA derivative, it is not necessary thatall of the double bond moieties of the cinnamic acid propyl esterresidue in the photo-reactive HA derivative are bound to formcyclobutane rings, but only some of the moieties may be bounded to formcyclobutane rings.

Hereinafter, in the cross-linked HA derivative, the ratio (%) of thecinnamic acid propyl ester residues contributing to the formation of thecyclobutane ring structures, to the cinnamic acid propyl ester residueswhich are present in the photo-reactive HA derivative, is referred to as“a degree of cross-linking”. For example, if 20 cinnamic acid propylester residues (monomer) are dimerized in the photo-reactive HAderivative into which 100 cinnamic acid propyl ester residues areintroduced, 10 dimers are produced, and the degree of cross-linking is20%.

The degree of cross-linking in the cross-linked HA derivative used inthe invention is not particularly limited, but preferably 5% to 40%,more preferably 7% to 35%, and further preferably 10% to 30%.

When the formation of the cyclobutane rings is performed bycross-linking based on the light irradiation, the concentration of thereaction solution in performing the cross-linking is preferably 0.5% to3.0%, more preferably 0.7% to 2%.

The cross-linked HA derivative may be free, without forming a salt, ormay form a pharmaceutically acceptable salt. Examples of thepharmaceutically acceptable salt of the cross-linked HA derivativeinclude sodium salts, potassium salts, magnesium salts, and calciumsalts.

<2> The Content of the Cross-Linked HA Derivative of the Invention

The cross-linked HA derivative has a three-dimensional mesh structure.Therefore, a solution in which the cross-linked HA derivative isdissolved in an aqueous medium, has a physical property of hydrogelhaving viscoelasticity, and particularly, exhibits higherviscoelasticity than solution of sodium hyaluronate prepared in the sameconcentration exhibits.

The content of the cross-linked HA derivative in the pharmaceuticalcomposition of the invention is preferably 0.5 to 3.0% by weight pervolume, more preferably 0.7 to 2.0% by weight per volume, and morepreferably 1.0% by weight per volume.

The pharmaceutical composition of the invention may be formulated intovarious dosage forms, but usually preferably formulated into aninjection product which is a liquid formulation for injection.

The content as described above allows the injection of the invention tohave suitable fluidity for intra-articular administration using asyringe with an injection needle, and to pass through the injectionneedle of 18 gauges to 25 gauges. Accordingly, the pharmaceuticalcomposition of the invention is allowed to be used as an intra-articularadministration injection product (composition for injection).

<3> Dosage and the Like of the Pharmaceutical Composition of theInvention

The pharmaceutical composition of the invention is administered into thejoint, particularly into the knee joint of human. For example, in caseof a single administration into the knee joint, the pharmaceuticalcomposition is administered preferably in a dosage of 2 to 5 mL, andmore preferably a dosage of 2 to 3 mL. The pharmaceutical composition ofthe invention may be administered in the same dosage, or nearly the samedosage as the single dosage of the conventional IA-HA products formultiple administrations.

In addition, in regard to the single administration into the knee joint,the dosage (volume of the solution) of the pharmaceutical compositionmay be further reduced such that the weight of the photo-reactive HAderivative is in the range of 15 to 60 mg, preferably in the range of 25to 35 mg, and particularly preferably 30 mg per one adult patient (50 to70 kg).

The pharmaceutical composition of the invention may be administered atan administration interval of 1 week or more, similarly to theconventional IA-HA products. The pharmaceutical composition of theinvention has early onset of pain alleviation action, and the effectsare durable for a long period, and thus the administration interval canbe lengthened compared to the conventional IA-HA products. Thepharmaceutical composition of the invention has durable actions up to 13weeks or more, and more specifically from 13 to 26 weeks. From this, theadministration interval can be set to 13 weeks or more, and furthermorein the range of 13 to 26 weeks. The pharmaceutical composition of theinvention may be used for durable effects up to at least 13 weeks, andfurthermore for durable effects up to 26 weeks. Considering a series oftreatments of the current IA-HA products is performed for every 26weeks, the pharmaceutical composition of the invention can be acontinuous type IA-HA product that can be continuously administered by asingle administration every 26 weeks.

<4> Coverage and the Like of the Pharmaceutical Composition of theInvention

The pharmaceutical composition of the invention has a pain relief actionor pain improvement effect for human joint disease. The pharmaceuticalcomposition of the invention has early onset of therapeutic effectsafter administration. That begins to show nearly maximum effects in theperiod between 1 week and 3 weeks after the administration, and theeffects are durable for 13 weeks or more, and furthermore for 26 weeks.This “therapeutic effect” is not particularly limited as long as it isan effect of improving symptoms of a human joint disease, but includesan effect of improving physical function, an effect of improvingstiffness, an effect of relieving pain, and the like as examplesthereof, and is preferably an effect of relieving pain.

The pharmaceutical composition of the invention has onset of suchimprovement effects between 1 week and 3 weeks after a singleadministration, and is characteristically durable for an ultralongperiod such as least 13 weeks, and furthermore 26 weeks.

The pharmaceutical composition of the invention may include additivessuch as a solvent, a pH regulator, a tonicity agent and a stabilizer,which are used in usual preparation of products for injection, ifnecessary unless they cause loss of desired effects, and causeside-effects. For example, examples of the solvent for the cross-linkedHA derivative include water for injection, physiological saline, andphosphate buffer saline. Further, examples of the additives also includesodium dihydrogen phosphate, sodium hydrogen phosphate, and sodiumchloride, which are used as a pH regulator or a tonicity agent in thepreparation of a usual injection product.

In addition, the pharmaceutical composition of the invention achievesearly onset of prominent therapeutic effects after a singleadministration. As shown in Examples described below, particularlyregarding the pain-relieving effects, about 90% or more of the maximumtherapeutic effects are achieved at 3 weeks after the administration ofthe pharmaceutical composition of the invention. Such rapid-onset andprominence of the pharmaceutical composition of the invention are notfound with conventional IA-HA products, and thus it is also consideredthat the active ingredient of the invention has a potential to havedifferent mechanisms from those of the conventional IA-HA products,whereby to have actions such as rapid-acting analgesic action. In otherwords, it has been found for the first time in the invention that thecross-linked HA derivative of the invention has a potential to havedifferent mechanisms from those of the hyaluronic acid component in theconventional IA-HA products in pain improvement action.

In addition, as shown in Examples described below, a group to whom thepharmaceutical composition of the invention is administered, hadsignificantly fewer patients who experienced pain again to be requiredretreatment at 26 weeks after an initial single administration comparedto the PBS-administered group. This results the administration of thepharmaceutical composition of the invention had prominently delayedrecurrence of pain.

For reference, ARTZ (registered trademark, manufactured by SEIKAGAKUCorporation), which is one of commercially available IA-HA products, isan intra-articular injection fluid with a volume of 2.5 mL per oneampule or one syringe, and a basic prescription thereof is one ampule orone syringe per single administration per week 5 times continuously.Consequently, the dose of ARTZ used in the single treatment course is12.5 mL. In addition, Synvisc-One (trademark, manufactured by GenzymeCo.) is used as 6 mL single administration in a single injection as aprescription thereof.

Overall, the pharmaceutical composition of the invention is based onthree main merits: single administration; small dosage; and longtherapeutic effects, and may be also used, for example, as a formulationfor a single administration every 3 months to a half year for a chronicjoint disease. Needless to say, the pharmaceutical composition of theinvention may be also used as a formulation that is administered at aninterval of 6 months or more in consideration of the durability of theimprovement effects in patients and patients' condition in symptom leveland the like. As a matter of course, only a single administration, i.e.,only a single treatment is also possible.

Hereinafter, the present invention will be further explained withreference to Examples, but the technical scope of the invention is notlimited thereto.

PREPARATION EXAMPLE Preparation of Cross-Linked HA Derivative

According to the method described in International Publication PamphletWO 2008/069348 other than using sodium hyaluronate having a weightaverage molecular weight of 900000 to 1000000 and cinnamic acid3-aminopropyl hydrochloride as raw materials, a cross-linked hyaluronicacid derivative having 10% to 25% of a degree of substitution and 10% to30% of a degree of cross-linking was appropriately prepared and asolution of the cross-linked hyaluronic acid derivative having aconcentration of 1.0% by weight per volume was prepared This solution isreferred to as “test substance” below.

EXAMPLE 1 Study Methods

A multi-center, double-blind, parallel-group controlled study wasconducted for patients with knee osteoarthritis, and effectiveness of asingle injection of the cross-linked HA derivative of the invention wasverified. Phosphate buffered saline (PBS) solution was used as a placebocontrol.

The screening of patients was performed based on the inclusion criteriaand the exclusion criteria described below before 1 to 2 weeks of theadministration of the test substance. Patients who met the criteria wererandomized to a group to whom the cross-linked HA derivative of theinvention was administered, or a group to whom the PBS was administered.The cross-linked HA derivative group had 249 patients, and the PBS grouphad 128 patients (a total of 377 patients).

To each of the patients in the cross-linked HA derivative administrationgroup of the invention, the test substance was single injectedintra-articularly into the one affected knee in the dosage of 3mL/joint. To each of the patients in the PBS administration group, PBSwas single injected in the same manner. Physicians who performed theadministration examined the affected knee of the patients and aspiratedthe fluid in the joint if the effusion presented prior to theadministration.

The improvement effects were assessed based on the assessment methoddescribed below at the time points of Week 1, Week 3, Week 6, Week 9 andWeek 13, respectively after the injection.

In addition, acetaminophen as a rescue medication was distributed oneach assessment day, and the patients were allowed to take up to 4000 mgacetaminophen per day. In addition to acetaminophen, the patients wereallowed to take non-steroidal anti-inflammatory analgesic drugs,over-the-counter drugs (OTC), herbal product and chondroprotectiveagents during the study period only if the patients had continued totake such drugs at a stable dose for more than four weeks beforeadministration of the test substance. In addition, intermittent use ofopioid analgesic drugs were also allowed during the study. However, for24 hours before each assessment day, any concomitant therapy wasprohibited.

[Inclusion Criteria and Exclusion Criteria]

(1) Inclusion Criteria

Patients who meet all of the following criteria can be qualified forthis study except those met any one of the exclusion criteria describedbelow.

Patients between the ages of 40 and 80 years, who have a symptom ofosteoarthritis of the knee.

Patients who have knee pain while standing or walking at least 4 weeksin duration.

Patients who have Kellgren-Larence grade 1 to 3 by X-ray.

Patients who have Western Ontario and McMaster UniversitiesOsteoarthritis Index (WOMAC (registered trademark)) pain subscore≧40 mmin the affected knee and 20 mm in the contralateral knee. Herein, WOMAC(registered trademark) was measured by a 100 mm. Visual analog scale(VAS).

Patients who have willingness to discontinue current OA treatment otherthan allowed concomitant therapies.

(2) Exclusion Criteria

Patients who have Kellgren-Larence grade 4 by X-ray.

Patients who have inflammatory diseases of knee in the affected otherthan OA; patients who have severe knee joint effusion; or patients whohave severe false alignment of the axis of the knee.

Patients who have history of joint replacement of knee or hip; patientswho had knee joint surgery within previous 12 months; patients who hadarthroscopy within 3 months; or patients who had intra-articularadministration of a hyaluronic acid product within previous 6 weeks.

Patients who have serious systematic arthropaties/infectious skindisease in the affected knee for assessment.

[Assessment Method]

Effectiveness of the cross-linked HA derivative was assessed by usingWOMAC scoring (The Journal of Rheumatology 1988; 15:12, p. 1833-1840)developed by Dr. Nicholas Bellamy. Herein, WOMAC is a registeredtrademark. Hereinafter, indication of this registered trademark will beomitted.

The WOMAC scoring used herein is a method in which patients arequestioned for total 24 items (Total) composed of 3 parts: Pain,Stiffness and Physical function, and they are scored based on theanswers.

In this study, the primary measurement was WOMAC pain subscore, and thesecondary measurements were WOMAC stiffness subscore, WOMAC Physicalfunction subscore, and Total WOMAC score.

The WOMAC scoring is patient's reported outcome, which is established asthe assessment method of OA, which is composed of total 24 questionsabout Pain, Physical function and Stiffness as described above. Theanswering method to the questions includes 2 kinds: VAS (Visual AnalogScale) and Likert scale. VAS is a method in which patients indicatedegrees of their own feelings for each question on a 100 mm line and thedegree is determined by the position. The position may be represented bya distance from the left end on the scale. On the other hand, LikertScale is a method in which patients indicate degrees of their ownfeelings for each questions by 5 categorical scales. In this study, VASis used in the assessment of the degrees of the pain, the physicalfunction and the stiffness of patients.

For example, patients are asked the same questions related to pain ineach assessment before and after administration, and the patients answerby indicating the position (degree) in the scale. Based on thedifference between the distance indicated by patient before theadministration (pre-administration reference value (Baseline)) and thedistance indicated by patient in each assessment after theadministration, the improvement effects are converted to numeral values.

The WOMAC score is widely used as an index of OA therapeutic effects,and the reliability and responsibility of WOMAC score on OA therapeuticeffects has been also validated (The Journal of Rheumatology 2000; 27:11, p. 2635-2641).

Effectiveness analyses were conducted using intention-to-treatpopulation (ITT population) and per protocol population (PP population).The ITT population had a total of 375 patients in which 247 patientsadministered the cross-linked HA derivative of the invention and 128patients administered the PBS. Two patients who did not have anypost-injection visit were excluded.

The PP population had a total of 344 patients in which 229 patientsadministered the cross-linked HA derivative of the invention, and 115patients administered the PBS. Patients who violated the protocol ofthis study were excluded.

[Results]

Results of the PP population analysis for WOMAC pain subscore are shownin Table 1, and results of the ITT population analysis are shown inTable 2.

TABLE 1 Week 1 Week 3 Week 6 Week 9 Week 13 Mean value 20.8 mm 28.9 mm31.7 mm 31.7 mm 27.8 mm of cross- (24.50) (25.52) (28.00) (28.47)(29.84) linked HA derivative (standard deviation) Mean value 19.1 mm20.9 mm 23.4 mm 25.7 mm 20.5 mm of PBS (24.71) (24.50) (26.64) (25.93)(28.66) (standard deviation)

TABLE 2 Week 1 Week 3 Week 6 Week 9 Week 13 Mean value 20.7 mm 28.7 mm31.2 mm 31.7 mm 27.8 mm of cross- (24.09) (25.23) (27.61) (27.91)(29.26) linked HA derivative (standard deviation) Mean value 19.8 mm21.3 mm 24.7 mm 27.4 mm 22.6 mm of PBS (24.61) (25.00) (27.31) (26.46)(29.31) (standard deviation)

The cross-linked HA derivative group of the invention showedstatistically significant improvement at the time point of Week 3 afterthe administration over the PBS group, and also lasted its effects afterWeek 3. The PP population showed statistically significant differenceover the PBS group with a p-value of 0.05 or less at the time points ofWeek 3, Week 6 and Week 13. These analyses showed advantage for thecross-linked HA derivative group of the invention though there was nosignificant difference at Week 9.

In addition, a figure representing the results of the model-estimatedregression analysis in the ITT population is shown in FIG. 1. Inanalyses of pain improvement for 13 weeks after the administration, thecross-linked HA derivative administration group improved painstatistical significantly over the PBS administration group through Week1 to Week 13 and through Week 3 to Week 13. The p-value between Week 1and Week 13 after the administration was 0.0483, and the p-value betweenWeek 3 and Week 13 after the administration was 0.0495, both of whichshowed statistically significance over the PBS group.

Furthermore, the improvements of each WOMAC score at the time point ofWeek 13 by the regression model were analyzed using the PP population.The results are shown in Table 3. The cross-linked HA derivative groupshowed statistically significant improvement in WOMAC pain subscore overthe PBS group at the time point of Week 13 after the administration. Thecross-linked HA derivative group showed statistically significantimprovement both in Total WOMAC score and WOMAC Physical functionsubscore, which are secondary measurements for effectiveness, and showedstatistically significant difference over the PBS group. Although therewas no statistically significant difference, WOMAC stiffness subscoreshowed favor trend in the cross-linked HA derivative group.

The Estimated difference below is the difference calculated using theregression model.

TABLE 3 95% Confidence Interval (CI) Estimated Lower value, Upperdifference value p-value WOMAC Pain 7.41 0.54, 14.28 0.035 SubscoreTotal WOMAC Score 7.27 0.60, 13.95 0.033 WOMAC Physical 7.30 0.54, 14.050.035 function Subscore WOMAC Stiffness 6.82 −0.22, 13.86   0.058Subscore

In addition, Strict OMERACT-OARSI Response was analyzed to verify theclinical usefulness. Statistically significant improvement wasdemonstrated for the cross-linked HA derivative group (see Table 4).

Strict OMERACT-OARSI Response defines patients who reported not lessthan 50% and at least 20 mm of improvement from baseline in WOMAC painsubscore or WOMAC Physical function subscore, as a high responder. Thetotal of these responder groups is referred to as the StrictOMERACT-OARSI responder.

TABLE 4 Odds ratio p-value Strict OMERACT-OARSI 1.74 0.012

In addition, regarding the early onset of the improvement effect, themean improvement from the baseline for WOMAC pain subscore, Total WOMACscore, WOMAC Physical function subscore and WOMAC stiffness subscore atWeek 3 was compared between the cross-linked HA derivative group and thePBS group. The WOMAC pain subscore showed the improvement effectexceeding 90% of the maximum improvement effect at Week 3, and thep-value that represents the statistically significance of thecross-linked HA derivative group to the PBS group is estimated (Table5). The p-value was less than 0.05 (p<0.05) in any other assessments,which showed statistically significant difference.

TABLE 5 P-value at Week 3 WOMAC Pain Subscore 0.0065 Total WOMAC score0.0129 WOMAC Physical function Subscore 0.0205 WOMAC Stiffness Subscore0.0336

Furthermore, after completion of the 13 week observation with respect tothe administration of the cross-linked HA derivative or PBS, observationwas extended for further 13 weeks, to assess effectiveness of thecross-linked HA derivative group up to 26 weeks from the initialadministration.

WOMAC pain subscore was assessed at Weeks 16, 19, 22 and 26 from thefirst administration, and patients who did not meet the criteria belowwere chosen as the effectiveness-durable group with firstadministration, and the survival analysis was performed using Cox-hazardmodel for each treatment group.

Endpoint A: ≧40 mm in WOMAC pain subscore.

Endpoint B: ≧40 mm in WOMAC pain subscore, and improvement<20 mm frombaseline of the first administration.

Cox-hazard analysis showed effectiveness for the cross-linked HAderivative administration group in both Endpoints up to 26 weeks(Endpoint A: p=0.019, Endpoint B: p=0.027).

CONCLUSION

It was found that single injection of the cross-linked HA derivativeshowed durable improvement effects up to at least 26 weeks from theinjection.

The cross-linked HA derivative showed prominent improvement not only inthe pain subscore, but also in the physical function subscore and otherscores compared to PBS group, and thus demonstrated multi-dimentionaleffectiveness in a knee OA.

In addition, the cross-linked HA derivative showed the rapid-onset ofthe pain improvement at 3 weeks after the injection, and also showedstatistically significant difference compared with the PBS.

Furthermore, the cross-linked HA derivative showed significantimprovement effects up to 13 weeks, and furthermore up to 26 weeks. Inaddition, the cross-linked HA derivative group had no statisticallysignificant difference from the PBS group in the expression rate ofadverse events, and had no severe side-effect. These demonstrated highsafety as an intra-articular injection of the cross-linked HAderivative.]

INDUSTRIAL APPLICABILITY

The present invention provides a new agent for relieving pain in a jointdisease that shows early onset of pain-relieving effects afteradministration, and has long term durability up to 13 week or up to 26weeks, and is a continuous type therapeutic agent for joint diseasesthat greatly reduces a burden to patients, and thus has applicability inthe industry such as medical industry.

The invention claimed is:
 1. A method for relieving pain in a joint disease, comprising: administering to a human subject in need thereof a pharmaceutical composition comprising hyaluronic acid that is cross-linked by cyclizing a double bond in a moiety of a cinnamic acid in a partially amidated hyaluronic acid represented by Formula (1), to form a cyclobutane ring, [Ar—CH═CH—COO—(CH2)n-NH-]m-HA  (1) in which Ar represents an optionally substituted phenyl group, n represents an integer of 2 or 3, HA represents a carboxy residue of the hyaluronic acid, and m represents an amidation ratio of the hyaluronic acid to a total of a carboxyl group and is 3% to 50% relative to the total carboxyl group; and a pharmaceutically acceptable carrier, wherein the pharmaceutical composition is an injection product, wherein the cross-linked hyaluronic acid is 1% by weight per volume of the injection product, wherein a single dosage of the injection product is 2 to 3 mL, and wherein the pharmaceutical composition is a single-dose preparation that is administered at an interval of 13 weeks or more.
 2. The method of claim 1 wherein the pharmaceutical composition is used for durable effects up to at least 13 weeks.
 3. The method of claim 2 wherein the pharmaceutical composition is used for durable effects up to at least 26 weeks.
 4. The method of claim 1 wherein the subject suffers from a joint disease.
 5. The method of claim 1 wherein the subject suffers from pain from a joint disease.
 6. The method of claim 1 wherein the subject suffers from osteoarthritis of the knee. 